Integrated circuits are commonly manufactured through utilization of photolithographic projection exposure devices (e.g., step reduction or step and repeat reduction exposure devices and scanning reduction projection exposure devices). One example of such a photolithographic projection exposure device is a device entitled Micrascan which is offered by Silicon Valley Group of San Jose, Calif. With these types of exposure devices, a substrate or wafer having a photosensitive resist layer formed on one of its surfaces is exposed to ultraviolet light irradiated from an illumination source which may be, for instance, a mercury lamp. In this process, light irradiated from the illumination source is first passed through a photomask or mask of the exposure device and then onto the photosensitive resist layer of the substrate. A circuit pattern which is to be transferred onto the substrate is formed on the mask and by irradiating light through the particular pattern formed on the mask, the circuit pattern may be projected or transferred onto the substrate for use in creating the integrated circuit.
Needless to say, the capacity of an integrated circuit may be increased by transferring finer or higher density circuit patterns onto the underlying substrates. To transfer these higher density circuit patterns, projection exposure devices have been implemented which reduce the size of the patterns projected from the mask onto the substrate. However, by reducing the size of the pattern to be transferred, due to the diffraction effects of light and consequent reduction in resolution, the pattern detrimentally becomes distorted and, in some cases, results in the transfer of an inaccurate circuit or a circuit which is not true with respect to the original circuit pattern.
Thus, a need exists for a device which transfers or projects a reduced circuit pattern or image from a mask onto an underlying substrate with a minimal loss of resolution and minimal reduction of fidelity.